Remove Ceilometer tempest tests

Now Ceilometer and Aodh tempest plugins are implemented and all
tests and supported code is present in plugins.
-https://github.com/openstack/aodh/tree/master/aodh/tests/tempest
-https://github.com/openstack/ceilometer/tree/master/ceilometer/tests/tempest

NOTE- Need to keep config option 'CONF.service_available.ceilometer'
as it is being used in Congress tests in Kilo and Liberty branch and
Ceilometer tempest plugin is available since Mitaka.
If we remove that then, we will be breaking Congress gate for stable branches.

Change-Id: I0775bcc15dc9cbae6e075fe92f44b5f6c9b9d5d2
Depends-On: Ic0e6b72d8767d92cc63968c442c4ff65bb001cda
20 files changed